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Aug. 27, 1963 E, PFARRWALLER DOBBY 5 Sheets-Sheet l Filed Feb. 1, 1961 few/N PFHP/PWALLEQ. .12v /f Aug. 27, 1963 E. PFARRWALLER DOBBY 3 Sheets-Sheet 2 ABCD E Filed Feb. l,

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Aug. 27, 1963 E. PFARRWALLER DOBBY 3 Sheets-Sheet 3 Filed Feb. l, 1961 3,101,746 DOBBY Erwin Pfarrwaller, Winterthur, Switzerland, assignor to Sulzer Freres, SA., Winterthur, Switzerland, a corporation of Switzerland Filed Feb. 1, 1961, Ser. No. 86,492 Claims priority, application Switzerland Feb. 12, 1.960 7 Claims. (Cl. 139-68) The present invention relates `to Ia mechanism for controlling the operation of lifting blades forming part of a dobby for :actuating heddle frames in looms -for weaving.

It is known to yieldingly arrest control levers for actuating lifting blades, which lift and lower the heddle frames in a weaving machine, in their end positions. The control levers yare posi-tively moved `all the way frornone end position rto the other end position and ample standstill periods must be provided for the lifter rails 4to permit reliable engagement o-f the lifting blades by the lifter rails, `or the channels in the rails which engage the blades must be so wide yas to provide a large clearance between the rails :and the portions of the -blades which are engaged by the rails.

It is an object of the present invention to provide a mechanism for moving the lifting blades forming part of a dobby for actuating the heddle frames in a weaving machine to positions where the blades are `engaged or disengaged by lifter rails whereby engagement is obtained quickly and accurately so` that neither undesired long standstill periods of the rails nor large clearances between the rails and the portions of the blades engagable by the rails need be provided. The mechanism according to the invention includes -a snap device provided with force-ao cumulating means which is loaded during movement of the lifting blades Ifrom one end position to a position half-way between the two end positions yof the blades and which applies the accumulated force to the mechanism when the blades have passed the half-way position for snappingly moving the blades into the second end position. The mechanism also includes damping means -for counteracting the force applied 4.by the snap device and damping the movement of the blades when the blades approach their end positions. r[he new mechanism affords reliable and accurate operation of a dobby for ractuating heddle lframes of a weaving machine at greater speed and with less noise and vibrations than is possible with conventional dobbies.

The novel features which are considered characteristic of the invention are set forth with particularity .in the :appended claims. The invention itself, however, and additional objects and advantages thereof will best be understood from the following description of embodiments thereofy when read in connection with the accompanying `drawings wherein:

FIG. 1 is a diagrammatic longitudinal sectional view of 1a dobby according to the invention.

FIG. 2 is a diagrammatic part sectional, large scale elevation of 1a detail of :the mechanism shown in FIG. 1.

FIG. 3 is a large scale, diagrammatic, 4longitudinal sectional elevation of a damping device forming part of the dobby shown in FIG. 1.

FIG. 4 is a diagram illustrating the relative movements of parts of the dobby shown in FIG. 1.

Referring more particularly to FIG. 1 of the drawing, numeral designates the main drive shaft of a card- United States Patent O M 3,101,746 Patented Aug. 2 7, 1,963

ICC

controlled dobby 11. Fast on the shaft 10 are cams 12 for actuating a cam follower lever 13 which operates lifter rails 14 and 15, and cams 16 for actuating a follower lever 17 which actuates, by means of a rod 18, Va lever 19v which actuates control rails 23 and 24 by means of links 21 and 22. The shaft 10 is driven by a chain 25 receiving its drive from-a shaft 26 which is connected to the main drive shaft of the loom, not shown. The shaft 26 rotates twice as fast as the shaft lll.

The lifter rails 14, 15 cooperate with lifting blades 31, 32 which are provided with lugs 33, 34, respectively, adapted to be received in the channels of the rails 14 and 15 which have a U-shaped cross sectional configuration. A pair of lifting blades 31, 32 is provided for each heddle frame. The lifting blades forming a pair are pivotally connected to a rocking cam 35. The cams 35 'are swingable on la shaft 36 which is made `fast on the casing `of the dobby. Each cam 35 -actuates -a lever 37 which is swingable on a stationary shaft 38. The levers 37 are adjustably connected to levers 39 rocking on a shaft 41. A linkage 42 is adjustably and pivotally connected to `each lever 39 and to a heddle frame, not shown, for actuating the latter. The adjustable connections afford adjustment of the stroke of the heddle frame.

The lifting blades 31, 32 are controlled by needles 47 in response to the pattern of the holes in a pattern card 45 which is stepwisely advanced by :a card cylinder 46. The needles 47 actuate control rods `48. lf a needle drops into a hole of the pattern card, the end of Ithe rod 48 to which the needle is operatively connected islowered and moves into the operating range of rthe lower control rail 23 to afford actuation thereby. If there is no hole,

the end of the rod 48 is lifted and is in the `operating range of the :upper control rail 24. The rails 23, 24 laterally and substantially horizontally reciprocate in opposite directions between end positions in which the rails `are shown in FIG. 2.

Each rod 48 actuates a control lever 51 which is rockable von a shaft 52 `and provided with a horizontal arm 53. The llower end of a downwardly extending arm of the lever 51 is connected by links 54 and 55 to 4the lugs 33 and 34, respectively, of the lifting blades 31 and 32.

The horizontal arm 53 of the control lever 51 cof operates with a pawl 61, as seen in FIG. 2. The pawl 61 has Itwo abutments 62 and 63. A guide means `is placed between and spaced from the abutments. In the illustrated example the guide means is in the form of a. roller 64 mounted on the pawl ybetween the abutments 62 and 63. The end Iof the -arm 53 of the lever 51 is provided with two inclined surfaces 66 and 67. The surface 66 engages the labutment 62 and the surface 67 engages the roller 64 when the arm 53 is in Ithe upper.- most position. When ythe arm 53 is in the lower extreme position the surface 67 engages the abutment 63 and the surface 66 engages the roller 64. The pawls 61 have recesses fitting a shaft 68 which is rigidly connected lto the casing of the dobby. A spring 69 having one end connected to the casing of the dobby and the other end to a pawl maintains engagement of Ithe respective pawl with the shaft 68 and with the Ifree end of the arm 53.

Each arm 53 is connected by means of a rod 71 to a piston 72 placed in a cylinder -73 provided with a lateral opening 74 and lilled with oil. The axial extension of the piston 72 is smaller than the axial extension of the opening 74 in the axial direction ofthe cylinder 73. Since, due to the piston rod connected to the upper side of the piston, the amount of oil to be displaced below the piston is greater than the amount of oil to be displaced above the piston and an equal damping effect is desired in both directions of movement of the piston, the lower edge 75 of the piston 72 is bevelled (FIG. 3). A clearance 72 is provided between each piston and its cylinder to obtain the desired dashpot eect.

Since a control lever 5l is required for each heddle frame the number of cylinders 73 is equal to the number of controlled heddle frames. The cylinders 73 are formed by bores in a block 76 which is mounted on a bottom platte 77 which is removably connected to a part 7 S of the dobby housing which forms an -oil sump.

FIG. 2 shows the mechanism in a position in which the `control rail 24 has turned the lever 5l in clockwise direction so far beyond its middle position M that the force accumulated in the spring 69 while the arm 53 has moved from its lower end position to its middle position causes the pawl 6l to swing clockwise and the roller `64 to run along the surface 67 for snapping the arm 53 to the position E0. `In order to avoid vibrations of the lever 5l and to reduce the noise produced by the knocks of the free end of the arm 53 against `the abutment 62 and 63, the movement of the rod 71 is braked by the device '72, 73 before the free end of lthe arm 53 knocks against the abutment 62 or 63. If the roller 64 is omitted and merely a guide surface is provided, the surfaces 65 and 67 slide along the guide surface. f

With the arrangement according to the invention th lugs 33 and 34 can be made Ito snuggly fit the channels of the lifter rails 14, 15 whereby vibrations are eliminated. When the lifter rails 14 and 15 have reached their end positions the lugs 33 and 34 are quickly pushed into the grooves of the lifter rails 14 and l5 by the force accumulated in the spring 619 and no undesired standstill periods must be provided for the lifter rails.

'Ille ordinates of the diagram FIG. 4 represents .the strokes of certain parts of the mechanism and the abscissae represent the angular positions of the main shaft of the weaving machine. At each revolution of the main shaft of the weaving machine a weft thread is inserted into the shed and beaten up.

The shed is open at the position 180 shown at the left side of the diagram FIG. 4. Line -A indicates the position of the heddle frames which are in the extreme upper position at this moment and the line B represents the positions of the heddle frames which -are in the lowerrnost position at this moment. Line C shows the positions of the lifter rails 14 and l5 which are in the lowermost position at the 180 position of the loom shaft shown on the left side of FIG. 4. Line D shows the positions of the upper control rail 24 which is in the position shown in PiG. 1 when the loom shaft is in the 180 position shown on the left side of the diagram FIG. 4. The lower control rail Z3 whose positions are indicated by the line E in FIG. 4 is in the right end position shown in FIG. 1 at the 180 position of the loom shaft on the left side of FIG. 4.

Since the shaft 10 makes one half revolution at each full revolution of the main shaft of the loom, the lifter rails 13 and 14 (line C in FIG. 4) move from the lowermost position to the uppermost position upon a full revolution of the main loom shaft. The lifter rails 14 and 15 move from the uppermost position to lthe lowermost position upon the subsequent full revolution of the main loom shaft. The heddle frames can be lifted or lowered during a full revolution of the main loom shaft, depending on which of the lugs 33, 34 is received in the channel of one or the other of the lifter rails 14, `115.

rllhe control rail 24 moves from the left end position to the middle position during =the first full revolution the main loom shaft, stays at the middle position for a period of time during which control rods 48 may be lifted, and moves from the middle position to the right during completion ofthe revolution of the main loom CII shaft. The lower control rail 23 moves at the same time therefrom to the left end position. The control rails move in the opposite direction during the subsequent revolution of the loom shaft. In the position of the mechanism shown in FIG. 2, the needle 47 is in the lifted position, because there is no hole in the card 45 and the control rail 24 has moved the control rod 4S so far to the right beyond its middle position that the pointed free end 65 of -the arm 53 is so far above the roller 64 that the force accumulated in the spring 69 during the previous counter- ,clockwise swing of the pawl 61 snaps the latter in clockywise direction and accelerates the upward movement of the end 65 of the arm 53 whereby a hook 49 on the control rod 43 `is disengaged from a corresponding protuberance S0 of the control rail 24. This is also obvious from the diagram FIG. 4 in the lower part of which this moment is illustrated in a larger scale. IThe line D has a sinusoidal configuration between the angular positions and 195 (D1 and D2). The middle Iposition is at the angular position The force accumulated in the spring 69 begins to act at the angular position l5 0 and accelerates the control rod `48 with the hook 49 as indicated by the dotted line Dt in FlG. 4 relatively lto the control rail 2.4 with the proituberance 50. Therefore, the control rod 48, vthe control lever Sl and the lug 34 of the lifting blade yi2 have reached their end positions already Iat the angular position due to the snap action of the pawl 6l caused by the spring 69, whereas the protuberance 50 of the control rail Z4 does not reach its right end position until the loom shaft is in the position With the mechanism according to the invention the lugs 33 and 34 are completely inserted in the channels of the lifter rails .14 and 15 hidependeutly of the speed of the movement of the control rails- 23 and 24. This insertion of the lugs requires less time and is effected more reliably than in conventional dobbies.

I claim:

1. In a dobby for selectively actuating the heddle frames of a weaving machine reciprocatingly movable lifter rails, movable lifting blades individually engageable with said rails, and a control mechanism operatively connected to said lifting blades for moving said lifting blades into positions where the blades are engaged or disengaged by said rails, said Vmechanism including a member rockable between two end positions, movable snap means engaged and adapted to be moved by said member, said snap means including force-accumulating means adapted to be loaded upon movement of said member from one end position to a position half-way between the end positions and to apply the accumulated force to said member when the latter has passed the halfway position for snappingly moving said member towards the second end position, and damping means connected to said member for damping the movement thereof towards the second end position.

2. In a dobby as dened in claim 1 and wherein said snap means includes a pawl swingable on a stationary fulcrum, said force-accumulating means being connected to said pawl to be actuated thereby, said member having an arm having a free end provided with converging inclined surface portions, and ysaid pawl having a guide portion adapted to be slidingly engaged by said free end for swinging said pawl by said arm upon rocking of said member.

3. In a dobby according to claim 2 and wherein said guide portion is formed by a roller mounted on said pawl.

4. In a dobby according to claim 2 and wherein said pawl is provided with two end abutments and said guide portion is placed between and spaced from said abutments, one of said end abutments being engaged by said free end when said member is in one end position and the other abutment being engaged by said free end when said member is in the second end position.

5. In a dobby as deiined in claim 1 a casing having an oil sump, said damping means being in the form of a dashpot placed in said sump.

6. In a dobby as defined in claim 5 and wherein said dashpot includes a cylinder, a double acting piston reciprocable in said cylinder, said cylinder having an aperture substantially in the middle of the axial extension of the cylinder, the extension of said aperture with respect to the longitudinal axis of said cylinder being greater than the axial extension of said piston.

7. In a dobby according to claim 6 a piston rod connected to one side of said piston and operatively connected References Cited in the le of this patent UNITED STATES PATENTS Pfarrwaller July 7, 1953 Herard et al Apr. 18, 1.961 

1. IN A DOBBY FOR SELECTIVELY ACTUATING THE HEDDLE FRAMES OF A WEAVING MACHINE RECIPROCATINGLY MOVABLE LIFTER RAILS, MOVABLE LIFTING BLADES INDIVIDUALLY ENGAGEABLE WITH SAID RAILS, AND A CONTROL MECHANISM OPERATIVELY CONNECTED TO SAID LIFTING BLADES FOR MOVING SAID LIFTING BLADES IN POSITIONS WHERE THE BLADES ARE ENGGAGED OR DISENGAGED BY SAID RAILS, SAID MECHANISM INCLUDING A MEMBER ROCKABLE BETWEEN TWO END POSITIONS, MOVABLE SNAP MEANS ENGAGED AND ADAPTED TO BE MOVED BY SAID MEMBER, SAID SNAP MEANS INCLUDING FORCE-ACCUMULATING MEANS ADAPTED TO BE LOADED UPON MOVEMENT OF SAID MEMBER FROM ONE END POSITION TO A POSITION HALF-WAY BETWEEN THE END POSITIONS AND TO APPLY THE ACCUMULATED FORCE TO SAID MEMBER WHEN THE LATTER HAS PASSED THE HALFWAY POSITION FOR SNAPPINGLY MOVING SAID MEMBER TOWARDS THE SECOND END POSITION, AND DAMPING MEANS CONNECTED TO SAID MEMBER FOR DAMPING THE MOVEMENT THEREOF TOWARDS THE SECOND END POSITION. 